Automatic reclosing circuit interrupter



M. E. REMGAN AUTOMATIC EECLOSXNG CIRCUIT INTERRUPT'ER Fe April 3B., 1922 INVENTOR WITNESSES:

.Patented Dec. 1, 1925.

UNITED STATES PATNT orrlcr..

IAURICE REAGAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR '1"0 WESTINGr-- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION F PENNSYL- VANIA.

AUTOMATIC RECLOSING CIRCUIT INTEBBUTEB.

Application led April 18, '1922. Serial No. 555,184.

T0 all lwhom it may comem:

Be it known that I, MAURICE E. REAGAN, a citizen of the United States, anda resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have'invented a new and useful' Improvement inAutomatic Reclosing Circuit Interrupters, of which the following is a specification. y

My invention relates to automatically reclosing circuit interrupters and particularly to interrupters of the type known as sectionalizing switches. One obJect of my invention is to provide a sectionalizing switch that shall be opened automatically when the current that is transferred between the sections exceeds a predetermined value by reason of an overload or short-circuit condition upon one of the sections, and that shall be rcclosed when such abnormal condition is eliminated.

Another object of my invention is to provide acontrol system for a switch of the above-indicated character that shall render the sectionalizing switch operative to connect the two sections when the sum of the voltages, and, consequently, the average of the voltages of the two sections, attains or.

I exceeds a predetermined value.

Another object of my invention is to provide a system, of the above-indicated character, comprisin meansthat shall preclude the operation of t e control system until a predetermined intervalafter the opening of the sectionalizing switch. l

A further object of my .invention is to provide a control system, of the aboveindicated character, that shall eiect the reclosing or' the sectionalizing switch when both voltage and load conditlons upon both sections are normal and that shall derive its operating voltage from either section, thus -Bain operative irrespective of whether or Ynot ie two sections are independently energized.

In practicin my invention, I employ the principle set orth in Patent No. 1,363,666, issued December 28, 1920 to Joseph N. Mahoney and Walter M. Austin and assigned to the Westinghouse Electric and Manufacturing Company. In that patent is disclosed the novel means of arranging an operating coil of a sectionalizing switch which consists in connecting the operating coil beage value attains or exceeds a tween the mid point of a resistor that is"` connected between the two sections that are to be controlled and the return conductor of the system. The closing coil is `thus energized in accordance withthe average value of the potentials of both sections and the switch may be closed only when thatavervalue.

In the system herein set forth, I employ.;`

the arrangement disclosed by Mahoney and Austin in the above-mentioned patent and predetermined provide .other controlling devices that have,

been found desirable. I provide, fr example, an overload relay that controls the circuit ofthe operating coil of the sectionalizing switch and is latched in its open position, when actuated, tomaintai the operat ing coil de-energized.

Upon the openlng of the sectionalizing c,

The singlefigure of the accom drawing is a diagrammatic view o a control system for an automatic sectionalizing switch embodying my invention. F

Two circuit .section conductors 1 and 2 have a common return conductor 3 and are adapted to be connected normally by a circuit-controlling device or sectionalizing switch 4 while conditions in the circuits of both section conductors l and 2 are normal. When overload or short-circuit conditions oc-` cnr in either section, as, for example, in sec-` tica 2, the value of the current transferred between sections 1 and 2 attains or exceeds a predetermined value at which an overload rela. 5 is adjusted to operate. The sectionalizing switch 4 is thereupon permitted to"l opn to disconnectl the section conductors 1; an 2.

The interrupter comprises the maimswitch g et, an operating coil 6 and two auxiliary switches 7 andl 8 that are open when the latch member 12 against the force of a -spring 14 to such osition that the pivoted member. is released). The pivoted member is thereupon actuated by' a spring 26 to e'ect the closure of a switch 9.

When the sectionalizing switch 4 is actuated to disconnect the two sections 1 and 2, two .resistors 15 and 16, that are connected between the sections 1 and 2, are

rendered effective to provide means whereby the average value of the potential difference of the two circuits may be obtained.

After' the opening of the switch 4, the switch 8 is closed to connectthe operating coil 17 of a time element relay 18 between the mid point of resisto-rs 15 and 16 and the return conductor 3. After a predetermined interval determined bythe setting of the daslrpot 19 of the time-element relay 18, a switch 20 is closed to complete the circuit of the operating coil 21 of a potential relay 22. The coil 21 is connected in series with a resistor 23 between the mid point of the resistors 15 and 16 and the return conductor 3 through the switch 20.

When the average value' of the potential differences across lthe sections 1 land 2 attains a predetermined value corresponding to the setting of an adjustable means 24 of the potential relay 22, a switch 25 is closed.

The switch 25 controls the energization of the reset coilv 13 of the overload relay 5.v

Assumingthe occurrence of a short circuit or overload on the section 2,4 the excess current caused to traverse the switch 4 and the circuit conductor 1 would effect the actuation of the overload relay. 5 to open the switch 9. The sectionalizing switch 4 would thereupon open, and, after a predetermined interval controlled by the setting of the dashpot 19, the switch 20 would close.'

The closing of the switch' 25, however, would be eected only when predetermined load conditions obtained on the circuit 2 and'the conditions on the circuit 1 were normal.

During tests that were conducted to determine the sensitiveness of the arrangement, resistors having a resistance of 0.575 ohms were connected between the section conductor 2 and the conductor 3, the normal p voltage' of the circuit being 250 volts. The

overload relay 5 was adjusted to operate at a value of current corresponding to this condition, to open the sectionalizing switch 4. The resistors 15 and 16 each having a resistance of 5 ohms, the total resistance between the section 'conductor 1 and the conductor 3, including the load resistance on lthe section 2, was 10.575 ohms.

At a voltage of 250 volts on the section `1, the current through the resistors 15 and 16 and the load resistance on the section 2 would be 23.62 amperes. Under these conditions, the potential difference between the mid point of the resistors 15-and 16 and the conductor 3 that would be effective in energizing the coil 21 ofthe voltage relay 22 is,131.9 Volts.

Upon changing the value of the resistance connected to the circuit 2 to substantially 0.8 ohm, the resistance from the conductor 1 to the conductor 3 amounted to 10.8 ohms. The current traversing the 'circuit in-,luding that value of resistance at the vol age of 250 volts was 23.15 amperes. The potential difference that was eiective under this condition lof resistance for energizing the coil 21 of the voltageresponsive relay 22 was, therefore, 134.25 volts. The relay 22 operated at this value to close the switch 25 to energize the reset coil 13 of the overload relay 5. The switch 9 was thereupon closed and the operating coil 6 was energized to effect the reclosing of the sectionalizing switch 4. t

The potential relay 22, being sensitive to a difference of approximately 21/2 volts at a redetermined value of voltage across the coil 21 and its resistor 23, very sensitive control of the sectionalizing switch 4 may be obtained in accordance with predetermined values of resistance under overload orv shortcircuit conditions in either circuit. The sectionalizing switch 4 may, therefore, be opened when the resistance across either section l or 2 is lowered to vor below the value of 0.575 ohm and may be reclosed when the value of vthe resistance attains or exceeds 0.8 ohm. 4 t

By means of the arrangement herein disclosed, relatively great sensitivity in the operation of the sectionalizing switch is obtained by means of standard relays that are ruggedl constructed for satisfactory operation un er extreme service conditions.

My invention is not limited to the specific devices lthat are illustrated or to the specific arrangement that is shown, since modifications may be made therein within the spirit and scope of my invention, as set forth in the appended claims.

I claim as my invention: t

1. In an electrical distribution system having a common return conductor, the oom` bination with `a circuit-controlling device provided with an operating coil fOr connectineeee ing the 'tivo circuit section conductors ot the system, of tivo resistors connected between t e circuit sections, means for normally connecting the operating coil between the inidpoint ot the resistors and the common return conductor com rising e. resistor and e switch controlled v an overleed device,

4 ineens tor letcliing the switch in open posin tion zitter its operation, a voltage relay tor edecting the release ot seid switch when the average potential of the two circuit sections attains a predetermined velue, and e time-element relay for controlling tlie energizetion of the voltage relay.

2. ln :i system of distribution, the co1nbination with two circuit section. conductors? a common return conductor and connecting device provided with en operating coil for connecting the two section conductors., of an overleed switch for opening the circuit of the coil when excessive current traverses the connecting device to permit the connecting device to open, resistance Ineens for limiting the exchange of current when the connecting device is open, e control relay, en

electrical timing relay set into operation by the opening of the connecting ineens and operative after a predetermined interval to energize tlie control relay, and Ineens controlled by tlie control relay in liccordance with zi predetermined relation between the voltages of both circuit sections for reclosing the overload switch to reenergize the operating coil oft' the connecting means.

3. ln a system of distribution, the combination with tivo circuit section conductors, e common return conductor and e connecting device provided with an operating coil for connecting the two section conductors, of an over-load switch for opening the circuit of the coil when excessive current traverses the connecting device to permit the connecting device to open, resistance ineens' for limiting the exchange of current when the connecting device is openy e control relay, an electrical timing relay, an interlock switch controlled by the connecting device to control the energization of the timing relay, ineens controlled by the timing relay zitter a predetermined interval for energizing the control 1elny,\and means controlled by said control reley when the voltages of both circuit sections bear a predetermined relation for reclosing the overload switch to control the energization of the operating coil of the connecting Ineens.

In testimony whereof, l have hereunto subscribed my naine this 14th dey of April MAURICE E; REAGAN.. 

